Hannibal Board of Public Works personnel, plus a private contractor, were working on one of the city’s outdoor warning sirens on Wednesday morning. The siren being upgraded is located near the intersection of Fifth and Center streets.

According to John Hark, the city’s emergency management director, the work was part of a system-wide upgrade mandated by the federal government. The city’s siren system had to operate on a narrow band by Jan. 1, 2013, or be in violation of the government’s new guidelines.

Hark reports that the city’s eight oldest sirens have been given the capability to “talk back” to the control center, enabling them to report any problems. The city’s newer sirens have also received upgrades.

“What this does is really modernize all 16 of the sirens and brings them up to a federal standard,” said Hark.

The city plans to use its siren system on Thursday, March 7, as part of the state’s Statewide Tornado Drill. Hannibal’s sirens are scheduled to sound at 11 a.m.